| 摘要 |
Photochromic compounds represented by the graphic formula: <IMAGE> wherein: (a) R1 is selected from the group consisting of C1-C8 alkyl, phenyl, phen(C1-C4) alkyl, allyl and mono- and di-substituted phenyl, said substituents being selected from C1-C4 alkyl and C1-C5 alkoxy; (b) R2 and R3 are each selected from the group consisting of C1-C5 alkyl, phenyl, C1-C4 alkyl and C1-C5 alkoxy mono- and disubstituted phenyl, benzyl or combined to form a cyclic ring selected from the group consisting of an alicyclic ring containing from 6 to 8 carbon atoms (including the spiro carbon atom), norbornyl and adamantyl, and (c) R4 and R5 are each selected from the group consisting of hydrogen, C1-C5 alkyl, halogen, C1-C5 alkoxy, nitro, cyano and C1-C8 alkoxycarbonyl are described. Solvent systems which form photochromic compositions with the above compounds and articles containing the photochromic compound are described. The compound or compositions typically change from a colorless (nonexcited) or pale color, e.g., yellow, to blue after exposure to ultraviolet light. |
